The ''Gent'' stacked filter unit (SFU) sampler for the collection of atmospheric aerosols in two size fractions: Description and instructions for installation and use

Abstract

This report contains a description and general instructions for the installation and use of the Gent Stacked Filter Unit (SFU) PM10 sampler. The sampler operates at a flow rate of 16 litres per min. It collects particulates which have an equivalent aerodynamic diameter (EAD) of less than 10#m in separate coarse (2-10 //m EAD) and fine ( 10 /urn EAD particles is accomplished by a PM10 preimpaction stage upstream of the stacked filter cassette. The air is drawn through the sampler by means of a diaphragm vacuum pump, which is enclosed in a special housing together with a needle valve, vacuum gauge, flow meter, volume meter, time switch (for interrupted sampling) and hour meter. A list of manufacturers of the various components of the sampler is also given. 1 . DESCRIPTION OF THE STACKED FILTER UNIT SAMPLING LINE The Stacked Filter Unit (SFU) sampling line is shown schematically in Fig. 1. It consists essentially of the following components: a. a double (stacked) filter cassette (which should be loaded with two different Nuclepore filters); b. a black polyethylene container (which includes a pre-impaction stage for PM10) for the stacked filter cassette [note: PM10 = particulate matter smaller than 10 /vm equivalent aerodynamic diameter (EAD)]; c. an orange-coloured rain protection cover with two grey PVC clamps inside for mounting the black polyethylene container in the rain protection cover, and also with two steel clamps for holding the POLY-FLO tubing; d. a 40-cm long soft transparent tubing with a SWAGELOK nylon connector at one end and a SWAGELOK brass connector at the other end to connect the stacked filter cassette to the POLY-FLO tubing; e. POLY-FLO tubing (3/8 outer diameter, 1/4 inner diameter) with a SWAGELOK brass connector mounted at each end to make a connection from the transparent tubing to the pump setup (the length of this POLY-FLO tubing may vary from 1 meter up to an absolute maximum of 100 meter); f. a needle valve (WHITEY) to regulate the flow rate; g. a vacuum gauge; h. a vacuum pump (GAST diaphragm pump, model no. D0A-P109-FD or DOA-V114FD or equivalent); i. a gas flow meter (rotameter DWYER VFB-67-BV);